To protect the copyright of data of an audio content and a video content that are recorded to a record medium, a watermark of which copy management information as additional information is superimposed and embedded to the data of the contents has been developed. As an example of such a watermark, a method for inserting additional information into a low order bit of data of a content is known.
To protect the copyright of audio data, as copy management information embedded as a watermark to a content, SCMS (Serial Copy Management System) has been used. Using the SCMS copy management information, not only a copy management for allowing a copy operation to be freely performed and a copy management for prohibiting a copy operation, but a copy management in a plurality of generations can be performed.
To do that, data of a watermark is embedded to a low order bit of data of a content. The SCMS copy management information is recorded to data of the watermark.
However, when the copy management in a plurality of generations is performed using the SCMS copy management information, it is necessary to rewrite it.
For example, SCMS data is represented with information of two bits. When the SCMS data is “00”, it represents that the record medium is an original record medium of which a copy operation can be performed in only one generation. When the SCMS data is “01”, it represents that the record medium is a copied record medium of which a further copy operation is prohibited. When the SCMS data is “11”, it represents that the record medium is a record medium of which a copy operation can be freely performed. When a copy operation is performed with a record medium of which the SCMS data is “00”, the SCMS data is rewritten from “00” to “01” so that a copy operation can be performed in only one generation.
A process for rewriting such a watermark requires a larger load than a process for detecting such a watermark.
In addition, when a watermark is recorded, for example, CRC code added so that an error can be detected. When the SCMS data is changed (namely, rewritten), it is necessary to change the CRC code.
The applicant of the present patent application has proposed a technology of which data of a watermark is processed as a packet composed of 48 bits. In the packet, 16-bit error detection CRC code is added. In this case, to allow a copy operation in only one generation, when an original disc is copied, the SCMS data is rewritten from “00” to “01”. At that point, in addition to the rewriting of the SCMS data, it is necessary to rewrite the 16-bit CRC code. Thus, the required load increases.
In particular, a technology of which a copy management using a watermark is performed by firmware accomplished by a program written in a ROM, not by a dedicated IC, has been desired. However, since the processing capacity of the firmware is very small, the process for rewriting the watermark imposes a large load on the firmware.
As was described above, when copy generations are managed, it is necessary to rewrite the watermark. When the watermark is rewritten, it is necessary to rewrite the CRC code, too. Thus, the process for rewriting the watermark imposes an excessive load to the firmware.
Thus, an object of the present invention is to provide a reproducing apparatus and a reproducing method for a record medium, a data output controlling method, a data outputting method, an error detecting method, and a data outputting and reproducing method that allow a management requiring the rewriting of a watermark embedded in a content to be sufficiently performed by firmware without need to rewrite error detection code and error correction code.